<template>
  <div>
    <div class="shopcart">
      <div class="content" @click="toggleList">
        <div class="content-left">
          <div class="logo-wrapper">
            <div class="logo" :class="{'highlight':totalCount>0}">
              <span class="icon-shopping_cart" :class="{'highlight':totalCount>0}"></span>
            </div>
            <div class="num" v-show="totalCount>0">{{totalCount}}</div>
          </div>
          <div class="price" :class="{'highlight':totalCount>0}">￥{{totalPrice}}</div>
          <div class="desc">另需配送费￥{{deliveryPrice}}元</div>
        </div>
        <div class="content-right" @click.stop.prevent="pay">
          <div class="pay" :class="payClass">
            {{payDesc}}
          </div>
        </div>
      </div>
      <!-- 小球动画效果 -->
      <div class="ball-container">
        <transition-group name="drop" v-on:before-enter="beforeEnter"
          v-on:enter="enter" v-on:after-enter="afterEnter">
          <div v-for="(ball,index) in balls" v-show="ball.show" class="ball" :key="index">
            <div class="inner inner-hook"></div>
          </div>
        </transition-group>
      </div>
      <!-- 购物车详情列表 -->
      <transition name="fold">
        <div class="shopcart-list" v-show="listShow">
          <div class="list-header">
            <h1 class="title">购物车</h1>
            <span class="empty" @click="setEmpty">清空</span>
          </div>
          <div class="list-content" ref="foodlist">
            <ul>
              <li class="food" v-for="food in selectFoods">
                <span class="name">{{food.name}}</span>
                <div class="price">
                  <span>￥{{food.price*food.count}}</span>
                </div>
                <div class="cartcontrol-wrapper">
                   <CartControl :food="food"></CartControl>
                </div>
              </li>
            </ul>
          </div>
        </div>
      </transition>
    </div>
    <!-- 遮罩层效果 -->
    <transition name="fade">
      <div class="list-mask" @click="hideList" v-show="listShow"></div>
    </transition>
  </div>
</template>

<script>
import CartControl from '@/pages/cartcontrol/cartcontrol'
import BScroll from 'better-scroll'

export default {
  name: 'ShopCart',
  data () {
    return {
      balls: [
        {
          show: false
        },
        {
          show: false
        },
        {
          show: false
        },
        {
          show: false
        },
        {
          show: false
        }
      ],
      dropBalls: [],
      fold: true
    }
  },
  props:{
    selectFoods: {
      type: Array,
      default() {
        return [
          {
            price: 10,
            count: 1
          }
        ];
      }
    },
    deliveryPrice: {
      type: Number,
      default: 0
    },
    minPrice: {
      type: Number,
      default: 0
    }
  },
  computed: {
    listShow() {
      if (!this.totalCount) {
        this.fold = true;
        return false;
      }
      let show = !this.fold;
      if (show) {
        this.$nextTick(() => {
          if (!this.foodlist) {
            this.foodlist = new BScroll(this.$refs.foodlist, {
              click: true
            });
          } else {
            this.foodlist.refresh();
          }
        })
      }
      return show;
    },
    totalPrice() {
      let total = 0;
      this.selectFoods.forEach((food) => {
        total += food.price * food.count;
      });
      return total;
    },
    totalCount() {
      let count = 0;
      this.selectFoods.forEach((food) => {
        count += food.count;
      });
      return count;
    },
    payDesc() {
      if (this.totalPrice === 0) {
        return `￥${this.minPrice}元起送`;
      } else if (this.totalPrice < this.minPrice) {
        let diff = this.minPrice - this.totalPrice;
        return `还差￥${diff}元起送`;
      } else {
        return '去结算';
      }
    },
    payClass() {
      if (this.totalPrice < this.minPrice) {
        return 'not-enough';
      } else {
        return 'enough';
      }
    }
  },
  created() {
    // 监听加入购物车事件，执行小球动画
    this.$root.$on('cart-add', this.drop);
  },
  methods: {
    // 结算
    pay() {
      if (this.totalPrice < this.minPrice) {
        return;
      }
      window.alert(`支付${this.totalPrice}元`);
    },
    // 遮罩层隐藏
    hideList() {
      this.fold = true;
    },
    // 清空
    setEmpty () {
      this.selectFoods.forEach( (food) => {
        food.count = 0;
      });
    },
    // 详情列表展开切换
    toggleList() {
      if (!this.totalCount) {
        return;
      }
      this.fold = !this.fold;
    },
    // 小球动画
    drop(el) {
      for (let i = 0; i < this.balls.length; i++) {
        let ball = this.balls[i];
        if (!ball.show) {
          ball.show = true;
          ball.el = el;
          this.dropBalls.push(ball);
          return;
        }
      }
    },
    beforeEnter(el) {
      let count = this.balls.length
      while (count--) {
        let ball = this.balls[count]
        if (ball.show) {
          let rect = ball.el.getBoundingClientRect()
          let x = rect.left - 32;
          let y = -(window.innerHeight - rect.top - 22)
          el.style.display = ''
          el.style.webkitTransform = `translate3d(0,${y}px,0)`
          el.style.transform = `translate3d(0,${y}px,0)`
          let inner = el.querySelector('.inner-hook')
          inner.style.webkitTransform = `translate3d(${x}px,0,0)`
          inner.style.transform = `translate3d(${x}px,0,0)`
        }
      }
    },
    enter(el) {
      el.offsetHeight // 触发浏览器重绘，offsetWidth、offsetTop等方法都可以触发
      this.$nextTick(() => {
        el.style.webkitTransform = 'translate3d(0,0,0)'
        el.style.transform = 'translate3d(0,0,0)'
        let inner = el.querySelector('.inner-hook')
        inner.style.webkitTransform = 'translate3d(0,0,0)'
        inner.style.transform = 'translate3d(0,0,0)'
      })
    },
    afterEnter(el) {
      let ball = this.dropBalls.shift()
      if (ball) {
        ball.show = false
        el.style.display = 'none'
      }
    }
  },
  components: {
    CartControl
  }
}
</script>

<style lang="stylus" rel="stylesheet/stylus" scoped>
  @import "../../common/stylus/mixin.styl"

  .shopcart
    position: fixed
    left: 0
    bottom: 0
    z-index: 50
    width: 100%
    height: 48px
    .content
      display: flex
      height: 100%
      background: #141d27
      color: rgba(255, 255, 255, 0.4)
      .content-left
        flex:1
        font-size: 0
        .logo-wrapper
          display: inline-block
          position: relative
          top: -10px
          margin: 0 12px
          padding: 6px
          width: 56px
          height: 56px
          box-sizing: border-box
          vertical-align: top
          border-radius: 50%
          background: #141d27
          .logo
            width: 100%
            height: 100%
            border-radius: 50%
            text-align: center
            background: #2b343c
            &.highlight
              background: rgb(0, 160, 220)
            .icon-shopping_cart
              line-height: 44px
              font-size: 24px
              color: #80858a
              &.highlight
                color: #fff
          .num
            position: absolute
            top: 0
            right: 0
            width: 24px
            height: 16px
            line-height: 16px
            text-align: center
            border-radius: 16px
            font-size: 9px
            font-weight: 700
            color: #fff
            background: rgb(240, 20, 20)
            box-shadow: 0 4px 8px 0 rgba(0, 0, 0, 0.4)
        .price
          display: inline-block
          vertical-align: top
          margin-top: 12px
          line-height: 24px
          padding-right: 12px
          box-sizing: border-box
          border-right: 1px solid rgba(255, 255, 255, 0.1)
          font-size: 16px
          font-weight: 700
          &.highlight
            color: #fff
        .desc
          display: inline-block
          vertical-align: top
          margin: 12px 0 0 12px
          line-height: 24px
          font-size: 10px
      .content-right
        flex:0 0 105px
        .pay
          height: 48px
          line-height: 48px
          text-align: center
          font-size: 12px
          font-weight: 700
          background: #2b333b
          &.not-enough
            background: #2b333b
          &.enough
            background: #00b43c
            color: #fff
    .ball-container
      .ball
        position: fixed
        left: 32px
        bottom: 22px
        z-index: 200
        &.drop-enter-active, .drop-leave-active
          transition: all 0.4s cubic-bezier(0.49, -0.29, 0.75, 0.41)
          .inner
            width: 16px
            height: 16px
            border-radius: 50%
            background: rgb(0, 160, 220)
            transition: all 0.4s linear
    .shopcart-list
      position: absolute
      left: 0
      top: 0
      z-index: -1
      width: 100%
      transform: translate3d(0, -100%, 0)
      &.fold-enter-active, .fold-leave-active
        transition: all 0.5s
      &.fold-enter, &.fold-leave-to
        transform: translate3d(0, 0, 0)
      .list-header
        height: 40px
        line-height: 40px
        padding: 0 18px
        background: #f3f5f7
        border-bottom: 1px solid rgba(7, 17, 27, 0.1)
        .title
          float: left
          font-size: 14px
          color: rgb(7, 17, 27)
        .empty
          float: right
          font-size: 12px
          color: rgb(0, 160, 220)
      .list-content
        padding: 0 18px
        max-height: 217px
        overflow: hidden
        background: #fff
        .food
          position: relative
          padding: 12px 0
          box-sizing: border-box
          border-1px(rgba(7, 17, 27, 0.1))
          .name
            line-height: 24px
            font-size: 14px
            color: rgb(7, 17, 27)
          .price
            position: absolute
            right: 90px
            bottom: 12px
            line-height: 24px
            font-size: 14px
            font-weight: 700
            color: rgb(240, 20, 20)
          .cartcontrol-wrapper
            position: absolute
            right: 0
            bottom: 6px
  .list-mask
    position: fixed
    top: 0
    left: 0
    width: 100%
    height: 100%
    z-index: 40
    backdrop-filter: blur(10px)
    background: rgba(7, 17, 27, 0.6)
    &.fade-enter-active, &.fade-leave-active
      transition: all 0.5s
      opacity: 1
    &.fade-enter, &.fade-leave-to
      opacity: 0
      background: rgba(7, 17, 27, 0)
</style>
